1. Technical Field
The present invention relates to a liquid ejecting head that ejects liquid droplets through nozzle openings and a liquid ejecting apparatus and, in particular, to an ink jet recording head that ejects ink as a liquid and an ink jet recording apparatus.
2. Related Art
Typical examples of liquid ejecting heads include an ink jet recording head that has a vibrating plate as a portion of pressure chambers that communicate with nozzle openings for discharging ink droplets and deforms the vibrating plate with piezoelectric elements so as to add pressure to ink in the pressure chambers and thus discharge ink droplets through the nozzle openings. The piezoelectric elements used for the ink jet recording head are formed by evenly forming a layer of a piezoelectric material over an entire surface of a vibrating plate using a film forming technique and then cutting the layer into a shape corresponding to the pressure chambers by lithography, thereby forming an independent piezoelectric element per pressure chamber (for example, see Japanese Patent No. 3379106). In Japanese Patent No. 3379106, individual electrodes and a common electrode of a plurality of the piezoelectric elements are provided per piezoelectric element in a comb-like pattern, thereby maintaining the displacement magnitude of a piezoelectric layer and providing excellent discharge properties.
In such a liquid ejecting head, there has been a demand for increased piezoelectric element density for improving printing quality. However, to achieve a higher density, the piezoelectric elements need to be decreased in size, and thus the displacement magnitude deteriorates.
However, when the electrodes are thinned so as to maintain a displacement magnitude, electric resistance rises and voltage drops, so that the piezoelectric elements cannot be made to deform at an even displacement magnitude. This is particularly troublesome since discharge properties become uneven, depending on voltage drops, between the case in which piezoelectric elements are selectively driven and the case in which all the piezoelectric elements are simultaneously driven.
The above problems are found not just in ink jet recording heads but also in liquid ejecting heads that eject liquid other than ink.